An Accurate and Efficient Analysis of a MBSFN Network

A new accurate analysis is presented for an OFDM-based multicast-broadcast single-frequency network (MBSFN). The topology of the network is modeled by a constrained random spatial model involving a fixed number of base stations placed over a finite area with a minimum separation. The analysis is driven by a new closed-form expression for the conditional outage probability at each location of the network, where the conditioning is with respect to the network realization. The analysis accounts for the diversity combining of signals transmitted by different base stations of a given MBSFN area, and also accounts for the interference caused by the base stations of other MBSFN areas. The analysis features a flexible channel model, accounting for path loss, Nakagami fading, and correlated shadowing. The analysis is used to investigate the influence of the minimum base-station separation and provides insight regarding the optimal size of the MBSFN areas. In order to highlight the percentage of the network that will fail to successfully receive the broadcast, the area below an outage threshold (ABOT) is here used and defined as the fraction of the network that provides an outage probability (averaged over the fading) that meets a threshold.Comment: 5 pages, 4 figures, IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), 2014, to appea

Qualitative behavior of cosmological models combining various matter fields

The late time accelerated expansion of the universe can be realized using scalar fields with given self-interacting potentials. Here we consider a straightforward approach where a three cosmic fluid mixture is assumed. The fluids are standard matter perfect fluid, dark matter, and a scalar field with the role of dark energy. A dynamical system analysis is developed in this context. A central role is played by the equation of state $\omega_{eff}$ which determines the acceleration phase of the models. Determining the domination of a particular fluid at certain stages of the universe history by stability analysis allows, in principle, to establish the succession of the various cosmological eras.Comment: 18 pages, 7 figures, accepted in IJMP

Analysis of Multi-Cell Downlink Cooperation with a Constrained Spatial Model

Multi-cell cooperation (MCC) mitigates intercell interference and improves throughput at the cell edge. This paper considers a cooperative downlink, whereby cell-edge mobiles are served by multiple cooperative base stations. The cooperating base stations transmit identical signals over paths with non-identical path losses, and the receiving mobile performs diversity combining. The analysis in this paper is driven by a new expression for the conditional outage probability when signals arriving over different paths are combined in the presence of noise and interference, where the conditioning is with respect to the network topology and shadowing. The channel model accounts for path loss, shadowing, and Nakagami fading, and the Nakagami fading parameters do not need to be identical for all paths. To study performance over a wide class of network topologies, a random spatial model is adopted, and performance is found by statistically characterizing the rates provided on the downlinks. To model realistic networks, the model requires a minimum separation among base stations. Having adopted a realistic model and an accurate analysis, the paper proceeds to determine performance under several resource-allocation policies and provides insight regarding how the cell edge should be defined.Comment: 6 pages, 3 figures, IEEE Global Telecommun. Conf. (GLOBECOM), 2013, to appear. arXiv admin note: text overlap with arXiv:1210.366

Performance Analysis of Fifth-Generation Cellular Uplink

Fifth-generation cellular networks are expected to exhibit at least three primary physical-layer differences relative to fourth-generation ones: millimeter-wave propagation, antenna-array directionality, and densification of base stations. In this paper, the effects of these differences on the performance of single-carrier frequency-domain multiple-access uplink systems with frequency hopping are assessed. A new analysis, which is much more detailed than any other in the existing literature and accommodates actual base-station topologies, captures the primary features of uplink communications. Distance-dependent power-law, shadowing, and fading models based on millimeter-wave measurements are introduced. The beneficial effects of base-station densification, highly directional sectorization, and frequency hopping are illustrated.Comment: 6 pages, 5 figures, IEEE Military Commun. Conf. (MILCOM), 201